Powder bed fusion (PBF) is a layer-wise additive manufacturing (AM) process producing 3D parts through selectively melting polymer powders with an infrared radiation (IR) laser beam. While this process is extremely successful in printing commercially available polymer powders, most of the offered materials require high temperatures and energy to print while also requiring large amounts of solvents to produce polymer powders in multiple steps. This work describes the use of a novel low-melting (&lt; 80 <sup>o</sup>C) polymer for PBF, poly(octadecyl acrylate) (POA), and suspension polymerization to produce particles for application as a phase change material. Suspension polymerization is underutilized in the PBF literature, producing spherical particles with controlled sizes while only using water, a non-toxic solvent, for the process. Tuning stabilizer amounts, i.e., poly(vinyl alcohol), in suspension polymerization varied the particle sizes of the POA and varying temperatures controlled extent of crosslinking. 2 wt % stabilizer produced particles with a 148 µm mean size and 60 % gel fraction, which represented the smallest sizes and gel fractions of the series. The high degree of crosslinking may hender coalescence of particles during printing and thus solution-derived POA was also added via dry mixing. Static and dynamic powder flowability experiments determined Hausner ratio and avalanche angle of 100% solution-polymerized, 100% suspension-polymerized, and 50:50 mixture powders. The resulting powders exhibit properties amenable for PBF, but 50:50 was chosen to attempt 3D parts based on zero-shear viscosity. The 50:50 mixture produced multi-layered 3D parts thus proving the system potential for a novel material and particle manufacturing method for PBF. Differential scanning calorimetry (DSC) also measured latent heat and stability over 50 heat-cool-heat cycles of a printed part to confirm the effectiveness as a phase change material.

Suspension polymerization of octadecyl acrylate powders for 3D printing of phase change materials

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.